/*******************************************************************************
* Copyright 2012 University of Southern California
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This code was developed by the Information Integration Group as part
* of the Karma project at the Information Sciences Institute of the
* University of Southern California. For more information, publications,
* and related projects, please see: http://www.isi.edu/integration
******************************************************************************/
package edu.isi.karma.rep;
/**
* @author szekely
*
*/
public abstract class CellValue {
private static CellValue emptyValue = new StringCellValue("");
public static CellValue getEmptyValue() {
return emptyValue;
}
public boolean isEmptyValue() {
return this == emptyValue;
}
// Return the value as a string.
public abstract String asString();
@Override
public boolean equals(Object o) {
if (o instanceof CellValue) {
CellValue cv = (CellValue) o;
return cv.asString().equals(this.asString());
}
return false;
}
}